1. Field of Invention
This invention relates to foot strap structures, and more specifically to foot strap structures for swim fins.
2. Description of Prior Art
Prior art swim fin strap structures do not offer adequate sizing adjustability and adjustable security harness structures to prevent loss of the swim fin during rough water conditions such as heavy surf. Prior art tethers used as security devices for prevention of loss of surf fins are designed for surf fins having non-adjustable heel straps that are permanently molded to one size. Non-adjustable heel straps prevent compensation for slight variations in size and also do not allow for preferences in the degree of tightness of such heel straps. Such prior art tethers are also difficult to take off in the water and the user often must walk up onto dry land while still wearing the fins before being able to disconnect the tether and then remove the fin. For the same reasons, many such devices must be put one and engaged while on dry land. Both  of these situations are undesirable since wading in water is more difficult while wearing fins. The play between the user's foot and the foot pocket due to the lack of sufficient adjustability with non-adjustable surf fin heel straps cause significantly reduced propulsion during kicking strokes as well as chaffing of the skin, bruises and blisters, especially in rough water conditions. The occurrence of chaffing, bruises and blisters can greatly reduced endurance and enjoyment. Prior art straps also do not properly address the need for multi-dimensional adjustable support of the ankle region during strenuous kicking strokes.
Prior art adjustable heel straps are highly susceptible to loss in high surf conditions as the flexible strap material is easily pulled down the heel and off the foot by large waves. This is particularly a problem with bare feet or fin socks that lack a thick and rigid rubber sole.